1. Field of the Invention
The present invention relates to a stroller frame. It relates in particular to the field of strollers for transporting a very young child.
2. Brief Description of the Related Art
To push a stroller on the ground, its frame is typically equipped with wheels or casters. The invention deals in particular with the so-called “three-wheel” stroller frames, that is to say, stroller frames provided, at the front, with a single wheel or a single pair of twinned wheels, whereas, at the rear of the frame, there are distinctly provided two wheels or two pairs of twinned wheels, respectively on the left and right sides of the frame. This type of stroller frame is highly appreciated because it gives the stroller a particularly pleasing overall appearance, with a sporty look, which is particularly attractive to a young clientele, as well as for the fact that having the frame press on the ground in three areas forming the vertices of a forward-pointing triangle makes the frame extremely easy to handle. This type of stroller frame is thus recognized for its good rolling behavior on country paths and bumpy ground, particularly in cities where strollers have to negotiate sidewalks, staircases, etc.
However, the existing three-wheel stroller frames have a major drawback associated with their bulk: this type of frame makes it essential, for comfort and safety reasons, to provide for the wheels to have a relatively large diameter. Given these conditions, some users forego the purchase of this type of stroller frame because it is so difficult to stow away and transport when the stroller is not in use, and to load in and unload from transport vehicles.
In the field of so-called conventional strollers, unlike the three-wheel strollers, that is to say, in the field of strollers with a “four-wheel” frame, frames are known that allow for the two front wheels and the two rear wheels to be retracted, particularly for the purposes of stowing away the stroller. For example, in the recent document WO-A-2007/025551, the front and rear wheels of one and the same left or right side of a stroller can be simultaneously moved, relative to the frame of the stroller, from an extended service position, in which the wheels are extended vertically to roll on the ground, to a retracted storage position, in which the wheels are extended horizontally to be flattened against the frame. Other examples of four-wheel stroller frames that are retractable in this way are provided by the older documents FR-A-525 797, U.S. Pat. No. 2,429,763 and U.S. Pat. No. 4,659,096.
In practice, the teaching relating to four-wheel stroller frames cannot, however, be transposed to a three-wheel stroller frame because of the specific structure of this frame essentially consisting of a single front arm and two rear arms, respectively left and right. Thus, WO-A-03/097466 proposes a stroller frame of which the three wheels can be moved from an extended service position to a retracted storage position, but only in a way that is both successive, that is to say one wheel after the other, and complicated, that is to say after several manual actions on the part of the user in several different areas of the stroller frame.